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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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Armstrong air ultra V furnace. 3 led flashes and no heat.

Customer Question

Hello, Armstrong air ultra V furnace. 3 led flashes and no heat. Pilot won't light. Can you help?
Submitted: 1 year ago.
Category: HVAC
Customer: replied 1 year ago.
Here is my unit. I live in Minnesota and the house is getting awfully cold. Any help right away would be appreciated!
Expert:  gotoman for ac replied 1 year ago.

This is a pressure switch lockout. Looking at front of furnace you see the small motor. Kill power to furnace and turn it back on. This will clear faults. See if small fan motor runs or tries to run. Put your hand on it to see if it is trying to run. If fan runs clean the small hose fittings. The small hose that attaches and runs to switch upper right. Remove hose and clean small firings with paper clip. Also check to see if the vent pipe is blocked by snow or ice. Try this and let me know. Russ

Customer: replied 1 year ago.
Hi Russ. I tried all that last night. The small fan motor doesn't even try to run so I'm not sure if that's the issue.
Customer: replied 1 year ago.
The hoses and fittings are clear and the vent pipe is clear. Being the fan doesn't kick on I feel like that could be the issue
Expert:  gotoman for ac replied 1 year ago.

If you are comfortable with electricity unlug fan from connector and put 110 volts directly to fan. If fan runs motor is good. You have a smart valve for gas valve and there is a board in the blower compartment that gives the codes. It going to be fan motor or board. Russ

Customer: replied 1 year ago.
Ok thanks
Expert:  gotoman for ac replied 1 year ago.

Sequence of operation fan runs for about 15 seconds,ignitor comes on for a few seconds and gas valve energizes and flame is proven thru flame sensor. Russ